A solar panel does not work independently. It needs to be matched with the electrical system that receives, stores or converts the electricity it generates.
Proper compatibility is especially important for off-grid systems.
Understand The Load
Start by identifying the electrical loads.
Determine:
Daily energy consumption
Peak power demand
Operating hours
Starting current for applicable equipment
Required backup time
This information provides the basis for selecting the solar array.
Match The System Voltage
Small off-grid systems may use nominal 12V or 24V battery configurations.
Larger systems may use higher-voltage architectures.
The solar panel's electrical characteristics should be compatible with the charge controller and battery system.
Match The Charge Controller
Charge controllers have limits for PV input voltage, current and power.
These limits must not be exceeded when connecting solar panels.
MPPT charge controllers can operate the PV array around its maximum power point while managing battery charging.
Match The Inverter
For systems using AC appliances, the inverter converts DC electricity from the solar array or battery into AC electricity.
The inverter must be compatible with the system voltage and provide sufficient power for the connected loads.
Consider Panel Configuration
Panels can be connected in series or parallel.
Series connections generally increase voltage, while parallel connections generally increase current.
The final array configuration must remain within the operating limits of the inverter and charge controller.
Include Energy Storage When Needed
If electricity is required after sunset or during periods of poor sunlight, batteries may be required.
The solar array should be sized to supply current loads while also providing sufficient energy to recharge the battery.
Use The Complete System Specification
Panel wattage alone is not enough to determine compatibility.
A proper system review should include panel voltage, current, array configuration, battery specifications, charge controller limits and inverter requirements.